Silencer for explosive engines



Aug. 15, 1939 F. NEWTON SILENCER FOR EXPLDSIVE ENGINES Filed June 7, 1938 iraflkjVewforgmmm ATTORNEYS Patented Aug. 15, 1 9 39 UNITED STATES PATENT OFFICE snrm'oaa FOB EXPLOSIVE mamas Frank'Newton. Presidio of Monterey. Application June '1, 1938; Serial No. 212,313

n atmosphere through the medium of an air blast to permit the exhaust gases to pass with a minimum sound into the atmosphere.

A further object is to provide a silencer for increasing the power of airplane motors by decreasing conventional back pressure to about 4115M pounds less than normal.

Y A further object is to provide a device of this character which will be formed of a few strong, simple and durable parts, which will be inex- 16 pensive to manufacture, which will be devoid of baflies and which will not easily get out of order. With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter 20 fully described and claimed, it being understood that various modificationsmay. be resorted to within the scope of the appended claim without departing from the spirit or sacrificing any of the advantages of the invention.

25 In the accompanying drawing forming part of this specification, I a

Figure 1 is a longitudinal sectional view of a silencer constructed in accordance with the'invention, suitable for airplane engines.

'30 Figure 2 is a front elevation of the silencer shown in Figure 1- Figure 3 is a detail longitudinal sectional view showing a-modified form of the invention suitable ror automotive engines.

85- Referring now to the drawing in which like characters of reference designate similar'parts in the various views, l0 designates a cylindrical inner casing-of the silencer having a convex or other suitable front end wall H provided with a 40 pipe I! adapted to be connected tothe exhaust is sealed around the pipe I and hasit's front end portion flared outwardly to' provide a funnel I! which is open to the atmosphere. The rear end ll wall of the shcll'coacts with the exhaust pipe ll and tapered rear wall l5 of the inner tubular section in forming a trap for gases. A plurality oftubes 20 are disposedin an annular series around therear end, or gas trap, of the shell, these tubes extending longitudinally of the 5 trap and are open in the rear end to the atmos- 10 phere. Each tube is provided intermediate its endswith a branch pipe 22 which is inclined rearwardly at an acute angle to the axis of the tube and enters the gas trap of the shell through the tapered rear wal1'18 thereof. The end of the tube is beveled ed to extend parallel to the axis of the shell, and confronts the funnel shaped rear wall i5 of the cylindrical casing I0 near the forward end of the wall.

.In operation, gases from the airplane engine enter the cylindrical casing l0 through the pipe i2 and the .heat, or infra red rays, traveling at the speed of light, radiate in all directions and are ejected through the apertures It. Sound waves entering cylindrical casing l0 through pipe V I2 disperse in all directions with a speed of over 1000 feet a second and escape-through the aper-' tures iii. The deflectors H deflect the sound and heat rearwardly as indicated by the arrowheads between the inner cylindrical casing and the .outer cylindrical shell, such movement being accelerated by air pressure as, the air is scooped into the entrance ,funnel l9. Air currents passing over the apertures create a partial vacuum in the inner cylinder which assist greatly in removing heat and sound waves from 'the inner cylinder since the'transmission of sound waves in a par- [tial vacuum is very difli'cult;

The heat and sound waves move in the direction indicated by the arrows into the gas trap 40 until .they collide with the conical rear end wall of the outer shell and there, under pressure from cold air entering the'funnel IQ of the shell, heat and sound are dissipated. As the pressure in the ,Sas trap at the conical rear end of the outer by the suction created in the tubes 20 through the medium of air scooped into the entrance funnels 2| of-the tubes. from the airplane engine comprising solids such as carbon, move in a rectilinear direction indicated by the aligned axially disposed arrows in the pipe l2, casing l0 and pipe l6, and are dis: charged into the atmosphere.

The form of the invention shown in Figure 1 is adapted for use in connection with constant load engines such as airplane engines. The modified form of the invention shown in Figure 3 is adapted for use in connection with engines which are not under constant load, such as automotive engines. The only difierence between the form of the invention shown in Figure 3 and the form of the invention shown in Figure 1, is that the front end 23 of the outer shell 24 is substantially coniwaves from the inner cylinder through the ori- 4 fices 21.

It has been found in practice that the silencer increases engine power even over an engine not equipped with a mulfler. Airplane motors exhaust againstan atmospheric pressure of about 14.7- pounds over absolute zero. The silencer re-v duces this pressure to about 10 pounds in the The residue of spent gases area within the front end of the inner cylindrical casing ID, or about 4.7 pounds less back pressure.

From the above description it is though that the construction and operation of the invention will be fully understood without further explanation.

What is claimed is:

A silencer comprising an enlarged tubular inner section open at both ends and adapted to be interposed in the exhaust line of an explosive engine and formed with a plurality of apertures;

rearwardly extending deflectors overlying the apertures, an outer shell having a tapered rear portion sealed upon the exhaust line inrear of the inner tubular section, said. tapered rear portion coacting with the exhaust pipe and inner tubular section in forming a gas trap, said shell having the front end portion flared outwardly and open to the atmosphere to scoop air into the space between the inner section and outer shell and into the gas trap, a plurality of longitudinally 

